18000000081 has 12 divisors (see below), whose sum is σ = 29714285952. Its totient is φ = 10285714296.

The previous prime is 18000000071. The next prime is 18000000089.

It is a happy number.

18000000081 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 18000000081 - 2⁵ = 18000000049 is a prime.

It is a super-2 number, since 2×18000000081² (a number of 21 digits) contains 22 as substring.

18000000081 is a strobogrammatic number because it is the same when read upside-down.

18000000081 is a modest number, since divided by 81 gives 18 as remainder.

It is not an unprimeable number, because it can be changed into a prime (18000000089) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 142857081 + ... + 142857206.

It is an arithmetic number, because the mean of its divisors is an integer number (2476190496).

Almost surely, 2^18000000081 is an apocalyptic number.

It is an amenable number.

18000000081 is a deficient number, since it is larger than the sum of its proper divisors (11714285871).

18000000081 is a wasteful number, since it uses less digits than its factorization.

18000000081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 285714300 (or 285714297 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

It can be divided in two parts, 180000000 and 81, that added together give a palindrome (180000081).

The spelling of 18000000081 in words is "eighteen billion, eighty-one", and thus it is an aban number and an uban number.